JP2008221107A - Liquid separation membrane module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure which reduces the flow resistance of filtered water and a back washing solution, excellent in back-washability, and also excellent in productivity with respect to an inner pressure type liquid separation hollow fiber membrane module. <P>SOLUTION: The inner pressure type liquid separation hollow fiber membrane module has a widened flow channel cross sectional surface area for filtered water and a back washing solution by widening the gap between hollow fiber membrane bundles in the outlet side of filtered water and a case without decreasing the amount of the hollow fiber membranes packed therein by installing the hollow fiber membrane bundles at a position eccentrically to the opposed side of the filtered water outlet. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to an internal structure of an internal pressure type hollow fiber type liquid separation membrane module.

  Separation and purification technology based on membrane separation technology is highly evaluated for its features such as its advanced separation function and energy saving, and it is becoming increasingly popular. Examples of its application fields are production of fresh water by desalination of seawater and brine, surface water and groundwater drinking water, production of pure water and ultrapure water used in the semiconductor industry and pharmaceutical industry, household wastewater and industrial wastewater, Sewerage treatment of municipal sewage and water recovery from wastewater, recovery of valuable materials from fermentation liquor and waste liquid, etc., liquid treatment field, oxygen enrichment and nitrogen enrichment from air, helium recovery from natural gas It covers a wide range of fields, such as gas separation fields such as carbon dioxide separation in the third recovery of oil.

  A fluid separation membrane is a liquid separation membrane such as a reverse osmosis membrane, nanofiltration membrane, ultrafiltration membrane, microfiltration membrane, or oxygen-enriched membrane, nitrogen separation membrane, carbon dioxide gas separation based on the separation target and separation mechanism. It is classified as a gas separation membrane such as a membrane. On the other hand, when focusing on the form of the fluid separation membrane, it is classified into a hollow fiber membrane, a tubular membrane, a flat membrane, a spiral membrane and the like. In the present invention, among the fluid separation membranes, the invention is particularly about the internal pressure type hollow fiber type liquid separation membrane. Hereinafter, in the present invention, unless otherwise specified, the membrane module refers to an internal pressure type hollow fiber type liquid separation membrane assembled in a usable state by connecting a pipe.

  In recent years, there has been a worldwide movement to utilize a membrane filtration method using an ultrafiltration membrane and a microfiltration membrane as a turbidity removal means in water purification treatment. One of the reasons is that it is highly evaluated for its high filtration accuracy compared to the sand filtration method that has been widely used for water purification treatment in the past, and high removability of pathogenic protozoa that have chlorine resistance such as Cryptosporidium. it is conceivable that. In order to further spread the membrane filtration method, it is required to reduce the equipment cost and the operation cost. In order to meet such a demand, various improvements are being made to the membrane module and the membrane filtration system. For example, in order to reduce the operating cost, increase the water permeability per operating pressure, improve the ratio of the production water volume to the supply water volume, that is, the recovery rate, reduce the frequency of chemical washing, extend the membrane life, Etc. are considered effective. Further, it is considered effective to reduce the facility cost by increasing the water permeation amount per membrane module volume, increasing the size of the membrane module, and the like.

  From such a background, conventionally, as an improvement of the membrane module, an increase in the size of the membrane module and an increase in the amount of permeated water per membrane area have been promoted. However, this increases the pressure loss related to the permeate flow in the membrane module and decreases the amount of water per operating pressure, and increases the pressure loss related to the backwash liquid flow in the membrane module to reduce the cleaning efficiency and compensate for it. For this reason, the amount of cleaning liquid is increased to compensate for the increase in the amount of cleaning liquid, the reduction in the recovery rate, the backwashing pressure of the part far from the backwashing liquid inlet at the time of backwashing is reduced, and the part is not washed sufficiently. Problems such as an increase and a decrease in recovery rate, a decrease in film life, or an increase in the frequency of drug washing have become apparent. The following techniques which are considered to be useful for solving these problems are disclosed in the patent literature.

Patent Document 1 discloses a technique of providing a discharge thin film made of a double wall having a wave shape or a hole over substantially the entire length in the longitudinal direction of a capillary filtration membrane. The discharge thin film is connected to a discharge conduit provided in the center of the case in the longitudinal direction of the case, and the permeated water is discharged to the outside of the module through the discharge conduit. On the other hand, the discharged thin film serves as a backwash liquid channel for introducing backwash liquid outside the module during backwashing. According to this configuration, it is possible to prevent damage to the hollow fiber membrane due to a strong flow of permeated water, and it is possible to increase the filling membrane area as compared with the case where a discharge pipe is provided, and to improve the filtration capacity of the module. Are listed. However, since the discharge thin film is connected to the discharge conduit, the number of members is large, the structure is complicated, and the productivity is poor. In addition, it is difficult to uniformly and densely fill the hollow fiber membrane in the gap between the discharge thin films with a cross-sectional fan shape, and the packing density of the membrane cannot be increased, resulting in poor compactness and poor productivity. It is a problem.
JP 2000-246063 A

In Patent Document 2, a cylindrical water collecting body having at least a part of a net-like portion is provided at the center of the case, and a module for backwashing liquid at the time of draining permeated water out of the module and backwashing through this is provided. A technique for introducing the information into the network is disclosed. When this technology is applied to a membrane module having a permeated water outlet on the outer peripheral surface of the case, a communication channel that connects the water collector and the permeated water outlet is necessary. For this reason, the internal structure of the module becomes complicated, resulting in a problem that the productivity is inferior. In addition, since the flow path connecting the water collector and the permeate outlet is formed, it is impossible to fill the portion with a hollow fiber membrane, which reduces the effective membrane area and lacks compactness. End up.
JP 2005-270944 A

Patent Document 3 describes a technique for installing a hollow core membrane bundle in a protective cylinder formed with a constricted portion. According to this invention, the flow outside the hollow fiber membrane is improved and a module can be manufactured at low cost. Has been. However, the operation of filling the hollow cylinder with the constricted protective cylinder is complicated and difficult, and not only the productivity is inferior, but also there is a problem that the hollow fiber membrane may be damaged in the production process. .
Japanese Patent Laid-Open No. 10-337449

  The present invention has been made against the background of such prior art problems. That is, the object of the present invention is, firstly, the pressure loss in the permeate chamber that becomes the flow path of the permeate during permeation is low, and the pressure loss in the permeate chamber that becomes the flow path of the backwash liquid during backwashing is low. It is another object of the present invention to provide an internal pressure type hollow fiber type liquid separation membrane module with high energy efficiency and long life, in which the entire membrane module is uniformly washed. Secondly, it is to provide an internal pressure type hollow fiber type fluid separation membrane module which is simple in structure and excellent in productivity while solving the first problem.

As a result of intensive studies, the present inventors have found that the above two problems can be solved simultaneously by the means described below, and have reached the present invention. That is, this invention consists of the following structures.
(1) A cylindrical case provided with one or a plurality of permeate outlets on the outer peripheral surface,
A hollow fiber membrane bundle is provided in the cylindrical case,
The hollow fiber membrane bundle is sealed between the hollow fiber type separation membranes and between the hollow fiber type separation membranes and the case at both ends, and the hollow fiber type separation membrane lumens at both ends of the cylindrical case. Is open,
It comprises a substantially annular space in cross section that is a gap between the hollow fiber membrane bundle and the substantially cylindrical case, and comprises a permeate chamber that communicates with the permeate outlet,
With respect to the permeate chamber in a cross section that includes the center of the permeate outlet and is orthogonal to the long axis of the case, Lf is the width on the permeate outlet side and Lb is the width on the opposite side of the permeate outlet. / Lb> 1 An internal pressure type hollow fiber type liquid separation membrane module.
(2) The hollow fiber membrane bundle has a maximum length in the axial direction of the case of 60% or more of the effective length of the hollow fiber membrane and less than or equal to the case length, and a small bundle of water permeable fillers communicating with the permeate chamber. (1) The internal pressure type hollow fiber type liquid separation membrane module according to (1).
(3) The internal pressure type hollow fiber type liquid separation membrane module according to (1) or (2), wherein a width of the permeate chamber is Lf / Lb ≧ 1.5.
(4) The internal pressure type hollow fiber type liquid separation membrane module according to any one of (1) to (3), wherein a width Lf of a permeate outlet of the permeate chamber is 20% or less of an inner diameter of the case.

  According to the present invention, the operating pressure and the backwash pressure can be reduced, energy efficiency can be improved, and the operating cost can be reduced. In addition, since the entire membrane can be washed uniformly during backwashing, it is possible to reduce backwashing time, use backwashing liquid, extend backwashing interval, and extend membrane life, improve energy efficiency during operation, This has the effect of reducing costs. Furthermore, since the internal structure of the membrane module is simple, the manufacturing cost of the membrane module can be kept low.

  Here, the present invention will be described by taking as an example the case of obtaining purified water from surface water or groundwater using an internal pressure type hollow fiber type liquid separation membrane module.

  FIG. 1 is a schematic view showing an entire internal pressure type hollow fiber type water purification membrane module as an example of an embodiment in the case where there is one permeated water outlet 110 in the vicinity of the end with respect to the axial direction of the case. The membrane module includes a cylindrical case 100 and a pair of caps 200 and 300 that close the end portions in the axial direction. The case 100 and the caps 200 and 300 are fastened by fastening means 700. Inside the case 100, a hollow fiber membrane bundle 400 having a circular outer cross-sectional outer diameter made up of a number of hollow fiber membranes 410 wrapped in a hollow fiber membrane protection cylinder 420 is arranged so as to extend in the axial direction of the case. ing. The hollow fiber membrane bundle 400 is installed at a position that is eccentric to the side opposite to the permeate outlet 110. For this reason, the gap between the outer periphery of the hollow fiber membrane bundle 400 and the inner periphery of the case 100 is wide on the permeate outlet side. Narrow on the other side of the water outlet. The outer peripheral surface of the hollow fiber membrane protection cylinder 420 has a net shape or a wall shape with a large number of holes through which water can be passed with a water flow resistance that is negligibly small compared to the transmembrane pressure difference. The raw water is filtered by the hollow fiber membrane 410 to purify the water. The upper end portion and the lower end portion of each hollow fiber membrane 410 are sealed and fixed to the case body 100 by a sealing resin 500. That is, the sealing resin 500 is filled in the gap between the hollow fiber membrane 410 and the gap between the hollow fiber membrane 410 and the inner wall surface of the case main body 100, thereby fixing the hollow fiber membrane 410 in a liquid-tight manner. In the hollow fiber membrane 410, the upper and lower ends thereof are opened, and only the upper end and the lower end are fixed with the sealing resin 500, and the other intermediate portion fulfills the water purification function. The permeate chamber 800 is a space having a substantially annular cross section, which is a gap between the case 100 and the hollow fiber membrane bundle 400, and is partitioned by a sealing resin 500 at the upper and lower ends, the upper end, and the lower end. A permeate outlet 110 is formed near the upper end of the permeate chamber 800. On the other hand, the caps 200 and 300 are made of cap-shaped cap bodies 210 and 310, and openings 220 and 320 are formed, respectively. An air vent 120 (not shown) may be formed near the upper end of the permeate chamber 800. Further, a drain port 130 (not shown) may be formed near the lower end of the permeate chamber 800.

  FIG. 2 is a schematic diagram showing the entire internal pressure type hollow fiber type water purification membrane module as an example of the prior art when there is one permeate outlet 110 near the end with respect to the axial direction of the case. The point that the hollow fiber membrane bundle 400 is coaxially installed at the center of the case 100 is different from the example of the embodiment of the present invention shown in FIG. The circumferential gap is uniform on the permeate outlet side and on the opposite side of the permeate outlet.

  The flow of water when membrane filtration is performed by crossflow and when backwashing is described with reference to FIGS. As shown in FIG. 4, the pressurized raw water is supplied to the inside of the hollow fiber membrane through the opening 220, and a part or all of the raw water passes through the hollow fiber membrane and passes through the permeate outlet 110 to the outside of the membrane module. This flows into the production water, and the remainder flows out of the membrane module through the opening 320 without being filtered. Since raw water contains various contaminants, when the membrane filtration is continued, the contaminants accumulate on the membrane surface and increase the membrane filtration resistance. In order to remove the contaminants and prevent the membrane filtration resistance from increasing, it is common to perform backwashing periodically at intervals of several tens of minutes to several hours. At that time, as shown in FIG. 5, clean water or clean water containing an appropriate cleaning agent such as an oxidizing agent such as chlorine, an acid, an alkali, a surfactant, or a mixture thereof is supplied from the permeate outlet 110. Pressurized and discharged from one or both openings 220, 320. The backwash flow rate is appropriately adjusted according to conditions such as the degree of increase in membrane filtration resistance, the amount and type of contaminants, backwash time, type of cleaning liquid, etc. Generally, it is about 1.5 to 5 times. A large force is applied to the hollow fiber membrane 410 in the front portion of the permeate outlet 110 due to the direct hit of the cleaning liquid flowing in from the permeate outlet 110 so that the hollow fiber membrane is not damaged. A dispersion plate 600 is installed. FIG. 3 shows a schematic perspective view of the dispersion plate 600. If it is not desirable that the cleaning agent contained in the backwash liquid is mixed into the production water, it is recommended that the cleaning agent be mixed into the production water by rinsing with clean water or discarding the initial filtered water. Can be prevented.

  Considering the flow of permeated water in the membrane module, since the hollow fiber membrane bundle 400 is filled with the hollow fiber membrane 410 at a high density, a flow path is formed outside the hollow fiber membrane bundle. Permeated water mainly flows outside the hollow fiber membrane bundle rather than passing inside the hollow fiber membrane bundle. The permeated water that has flowed out of the hollow fiber membrane bundle flows toward the permeated water outlet 110 that discharges the permeated water from the membrane module, as indicated by thick arrows in FIG. The flow rate of the permeated water is small at a position far from the permeated water outlet 110 and increases cumulatively as the permeated water outlet 110 is approached. For this reason, in the conventional membrane module in which the distance between the outer periphery of the hollow fiber membrane bundle 400 and the inner periphery of the case 100 is equal regardless of the distance from the permeate outlet 110, the cross-sectional area of the flow path becomes closer to the permeate outlet 110. The amount of water flowed per unit was increased, a large pressure loss was generated, and wasted energy was consumed for the flow in the module. On the other hand, it is considered that the flow resistance of the entire membrane module can be reduced by adjusting the size of the channel cross-sectional area according to the size of the flow rate on the left. Here, when the means for adjusting the cross-sectional area of the channel on the left side is considered in a plane perpendicular to the long axis of the case, if the hollow fiber membrane bundle 400 is installed at a position offset to the opposite side of the permeate outlet 110, the permeate The gap between the hollow fiber membrane bundle 400 on the outlet 110 side and the case 100 is increased, the cross-sectional area of the flow path on the permeate outlet 110 side is increased, and the flow resistance of the permeate can be reduced, leading to the present invention. It was. Further, as a modification of the left invention, the same effect can be obtained by devising the cross-sectional shape of the hollow fiber membrane bundle 400 and widening the gap between the hollow fiber membrane bundle 400 on the permeate outlet 110 side and the case 100. I came up with it.

  On the other hand, considering the effect of the present invention in the case of backwashing, as shown by the thick arrows in FIG. 5, the backwashing liquid supplied from the permeate outlet 110 partially permeates the inside of the hollow fiber membrane. The remaining part flows toward the back of the membrane module. For this reason, the flow rate of the backwash liquid is large at a portion close to the permeate outlet 110, and the flow rate of the backwash liquid is cumulatively decreased as the distance from the permeate outlet 110 is increased. Since the magnitude of the flow rate corresponds to the magnitude of the cross-sectional area of the flow path, the pressure of the backwash fluid applied to the hollow fiber membrane is leveled, and the entire hollow fiber membrane is effectively washed.

In the present invention, the permeate chamber, which is the gap between the case and the hollow fiber membrane bundle, becomes the permeate flow path during permeation. Further, the permeate chamber functions as a flow path for backwashing liquid during backwashing. In the present invention, the channel widths Lf and Lb of the permeate chamber are defined as follows. FIG. 8 is a schematic cross-sectional view of a portion corresponding to the AA cross section of FIG. 1 in various exemplary embodiments of the present invention. On the left section,
(1) Assume an auxiliary line 1001 that has the center of the case as the origin and connects the centers of the one specific permeate outlet. The direction from the origin to the center of the specific one permeate outlet is defined as 0 °.
(2) Of the gap width between the case and the hollow fiber membrane bundle, the width in the 0 ° direction is Lf, and the width in the 180 ° direction is Lb.
However, the outer shape of the hollow fiber membrane bundle on the cross section perpendicular to the long axis of the cylindrical case and including the center of the specific one permeate outlet is the same as the outer shape of the hollow fiber membrane bundle on the module end surface. In such a case, the same measurement as described above is performed on the end face of the module. In any case, when the hollow fiber membrane bundle is covered with a water-permeable material such as a mesh, the thickness of the water-permeable material is included in the width of the gap between the hollow fiber membrane bundle and the case. To do.

  If Lf / Lb is slightly greater than 1, the effect of the present invention is obtained to some extent, but in order to obtain a clear effect, Lf / Lb is preferably 1.5 or more, and if it is 2 or more Further preferred. On the other hand, since the hollow fiber membrane bundle on the opposite side of the permeate outlet 110 may be in contact with the inner periphery of the case, the upper limit of Lf / Lb is infinite. However, unnecessarily increasing Lf is not a good idea because it leads to a reduction in the amount of hollow fiber membranes that can be filled in the membrane module. Considering this point, Lf is preferably 20% or less of the case inner diameter. It is more preferable to make it% or less.

  The hollow fiber membrane bundle 400 may be composed of a plurality of small bundles of hollow fiber type separation membranes. The cross-sectional outer shape of the small bundle may be any shape such as a circle, an ellipse, a polygon, and a fan. Further, a gap (hereinafter referred to as a gap between the small bundles) may be formed between the small bundles. When the gap between the small bundles is formed, the gap between the small bundles also functions as a flow path of permeated water and backwash water in cooperation with the gap between the outer periphery of the hollow fiber membrane bundle and the inner surface of the case, There is an effect of reducing the flow pressure loss in the hollow fiber membrane bundle 400. Providing the gaps between the small bundles is effective when the outer diameter of the hollow fiber membrane bundle is large, and particularly effective when the outer diameter of the hollow fiber membrane bundle is 100 mm or more. Between the small bundle gaps may be filled with a water permeable filler, and such an embodiment is suitable for the small bundle due to deformation of the small bundle even when there is a flow of permeated water and backwash water at a high flow rate. It is preferable because the clogging between the bundle gaps does not occur and the flow pressure loss effect is surely exhibited.

  When filling the water-permeable filler between the small bundle gaps, it is not always necessary to fill the entire gap between the small bundles. It may be partially filled, and the filler may not be filled particularly in a portion where the flow rate of the permeated liquid and the backwash liquid is small, such as a part far from the permeate outlet. The small bundle water-permeable filler preferably has a maximum length in the case axial direction of 60% or more of the effective length of the hollow fiber membrane and not more than the case length and communicates with the permeate chamber. Preferred examples of the small bundle of water-permeable fillers include a laminate of reticulated sheets and a three-dimensional reticulated body having a high porosity and a large pore diameter. For example, a three-dimensional network having a structure in which a net-like sheet having a thickness of about 0.5 to 5 mm is laminated or a large number of bent filaments having a wire diameter of about 0.5 to 5 mm are bonded to each other at the contact portion. Is mentioned. FIGS. 6 and 7 schematically show the flow of water during permeation and backwashing when a plate-shaped inter-small bundle water-permeable filler 900 is sandwiched between two small bundles having a semicircular cross section. Thus, in addition to the permeate chamber 800 which is the gap between the hollow fiber membrane bundle 400 and the inner periphery of the case 100, the small bundle water-permeable filler 900 also functions as a flow path for the permeated water and the backwash water. In addition, it is preferable to use a high-stiffness water-permeable filler between small bundles 900 because there is an effect of suppressing deformation of the hollow fiber membrane bundle when the membrane module is operated at a large flow rate. The cross-sectional shape of the small bundle of water permeable fillers is not particularly limited, but if they are arranged in a rectangular shape, a cross shape, a radial shape, or the like so that a part thereof communicates with the permeate chamber, the backwash pressure is reduced by the hollow fiber. It is preferably applied evenly to the entire membrane bundle and easy to manufacture.

  The permeate chamber 800 may be partially or entirely filled with a water-permeable filler as long as the flow resistance of the permeate and the backwash water is not greatly increased. When the permeated liquid chamber 800 is filled with the water permeable filler, it is not always necessary to fill the entire permeated liquid chamber. It may be partially filled, and it may not be filled in a portion where the flow rate of the permeated liquid and the backwash liquid is small, such as a part far from the permeated liquid outlet 110. In addition, it is preferable that the portion near the permeate outlet 110 is not filled with a filler, or a filler with particularly low water permeability is used. This is because the flow rate per channel cross-sectional area of this part is particularly high compared to other parts in the membrane module, and thus reducing the flow resistance of this part is highly effective in reducing the flow pressure loss in the permeate chamber. It is preferable that the permeated liquid chamber permeable filler has a length of 60% to 100% of the distance from the end of the case to the permeated liquid outlet and communicates with the permeated liquid chamber. Preferred examples of the permeate chamber filling material include a laminate of mesh sheets and a three-dimensional mesh body having a high porosity and a large pore diameter. For example, a three-dimensional network having a structure in which a net-like sheet having a thickness of about 0.5 to 5 mm is laminated or a large number of bent filaments having a wire diameter of about 0.5 to 5 mm are bonded to each other at the contact portion. Is mentioned. Moreover, when a thing with high rigidity is used for a permeate liquid filling body, there exists an effect which suppresses a deformation | transformation of a hollow fiber membrane bundle when operating a membrane module by a large flow rate, and it is preferable.

  The cross-sectional outer shape of the outer periphery of the hollow fiber membrane bundle in the present invention is substantially circular. If the outer diameter of the outer periphery of the hollow fiber membrane bundle is substantially circular, no wasteful space is generated in the case, the hollow fiber membrane can be filled with high efficiency, and the membrane module can be made compact. This is preferable because it is possible. A part of the preferred embodiment of the cross-sectional outer shape of the outer periphery of the hollow fiber membrane bundle is shown in FIG. The substantially circular shape in the present invention includes a circular shape, an elliptical shape, a regular polygon having 6 or more sides, and rounded corners of the regular polygon. In addition, the substantially circular shape in the present invention may be a shape obtained by combining a semicircle and a semi-elliptical shape whose major axis length is equal to the diameter of the semicircular shape on the left, or a shape obtained by combining two semi-ellipses having the same major axis length. In this case, it is preferable to arrange the short axis side toward the permeate outlet 110 side. Or the shape which cut off the permeate outlet 110 opposing part of these cross-sectional shapes may be sufficient. Furthermore, a hollow fiber membrane bundle having a shape of any one of these cross-sectional shapes is formed in advance, and a flow on the permeate outlet 110 side is inserted by means such as inserting a spacer into the gap between the hollow fiber membrane bundle 400 and the case 100. If end bonding is performed in a state where a part or the whole of the hollow fiber membrane bundle is deformed so as to widen the path, a shape in which the outer shape of the hollow fiber membrane bundle is distorted is fixed. The outer shape of the hollow fiber membrane bundle thus obtained is also included in the substantially circular shape in the present invention. Making the cross-sectional shape of the outer periphery of the hollow fiber membrane bundle into a circular shape, an elliptical shape, and a shape obtained by deforming a part of them makes the manufacturing process of the hollow fiber membrane bundle simple and highly reproducible, thereby reducing the manufacturing cost. Are particularly preferred.

  Although FIG. 1 shows the case where the position of the permeate outlet 110 is near the end of the case 100, it may be near the center in the length direction of the case 100 as shown in FIG. In the example of the embodiment of FIG. 7, an air vent 120 is provided near the upper end of the permeate chamber 800, and a drain port 130 is provided near the lower end of the permeate chamber 800. When there is air in the permeate chamber 800 when starting up the operation of the membrane module, the air in the permeate chamber 800 is permeated by the permeated water when the air vent 120 is opened and the drain port 130 is closed and the supply of raw water is started. Then, the air vent 120 is closed and the membrane filtration operation is started. Further, when the liquid in the permeate chamber 800 is to be discharged, such as when the membrane module is detached from the membrane filtration device, when the air vent 120 is opened and the drain port 130 is opened, air is passed from the air vent 120 to the permeate chamber. It flows in and the liquid in the permeate chamber 800 is discharged.

  The case 100 in the present invention is a substantially cylindrical container filled with a fluid separation membrane, and has at least one permeate outlet on the outer peripheral surface thereof. The permeated water outlet on the left functions as a fluid inlet / outlet port. In the use state of the fluid separation membrane, both ends of the case are coupled to the cap, or a bottom part integral with the case is formed. An opening may be formed in the bottom integral with the left cap or case. The material of the case and cap is not particularly limited, but engineering plastics such as vinyl chloride resin and polysulfone resin, various reinforced resins such as glass fiber reinforced resin, and corrosion-resistant metal materials such as stainless steel are suitable. The glass fiber reinforced resin is particularly lightweight as a case material because it is lightweight and excellent in corrosion resistance and has good adhesion to the liquid separation membrane sealing resin. Stainless steel is particularly preferable as a cap material because it is excellent in strength and corrosion resistance and can be easily connected to external piping. The case and cap may be uneven or colored according to functional or design requirements.

  The caps 200 and 300 in the present invention preferably include an end plate as a constituent element. There are various types of end plates, such as a dish shape, a regular semi-ellipsoidal shape, an approximate semi-elliptical shape, a hemispherical shape, and a flat mirror shape, and any shape may be used. By providing the end plate as a constituent element, the thickness can be reduced compared with a simple bottomed cylindrical type, and the weight can be reduced and the cost can be reduced.

  The fastening method of case 100 and caps 200 and 300 in the present invention is not limited to a specific method. It may be screwed, or a flange provided on the case and the cap may be fastened by a bolt and nut or a swing bolt and nut. Moreover, it is also possible to connect by various pipe joints, and V band coupling, a victic joint, Straub coupling (trademark), etc. are examples of a suitable fastening method.

  The material of the hollow fiber type separation membrane in the present invention is not particularly limited. Preferable examples of the membrane material include organic polymer compounds such as polysulfone, polyethersulfone, polyvinylidene fluoride, polyacrylonitrile, polyamide, and cellulose acetate, and copolymers, mixtures, and modified products containing these. Also, a ceramic film may be used. Further, the separation mode of the hollow fiber type separation membrane is not particularly limited. Any separation mode such as reverse osmosis membrane, nanofiltration membrane, ultrafiltration membrane, microfiltration membrane, etc. may be used.

  As mentioned above, although the example of embodiment of this invention was added, this invention is not limited to these, A various change is possible unless it deviates from the meaning.

  In addition, the liquid separation membrane module is a water purification membrane module made of an internal pressure type hollow fiber membrane, and the case where it is operated by a cross flow filtration method has been described as an example. It can be applied in the same way and demonstrates its effect. Further, the use is not limited to the water purification treatment, and it can be similarly applied to liquid separation membranes having different uses such as wastewater treatment and pretreatment of seawater desalination reverse osmosis membrane.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the examples.

(Method for producing hollow fiber membrane and method for measuring water permeability)
Polyethersulfone (manufactured by Sumitomo Chemical Co., Ltd., Sumika Excel (registered trademark) 4800G) and polyvinylpyrrolidone (manufactured by Nippon Shokubai Co., Ltd., K-30) were heated and dissolved in a mixed solution of dimethylacetamide and triethylene glycol to obtain a spinning dope. . Discharge the spinning stock solution from the outer slit of the double tube nozzle, and simultaneously discharge the aqueous solution of dimethyl ace, amide and triethylene glycol from the inner tube of the double tube nozzle, and after passing through the air, the aqueous solution of dimethylacetamide and triethylene glycol It was led to a coagulation bath consisting of and solidified. Washing with water and hot water washing were carried out, followed by drying with a hot air drier to obtain a hollow fiber membrane having an inner diameter of 0.8 mm and an outer diameter of 1.4 mm. The transmembrane pressure difference 0 extrapolation value of the water permeation flux at a water temperature of 25 ° C. was 30 m ³ / m ² / d / 100 kPa.

(Manufacture of membrane modules)
A bundle of hollow fiber membranes having a length of 1.2 m was made using 22560 hollow fiber membranes described above, and the outer peripheral part of the bundle was covered with a polyethylene net (thickness 2 mm). A hollow, covered with a mesh body on the left, in a substantially cylindrical case made of glass fiber reinforced resin with a length of 1066 mm and an inner diameter of 300 mm, which has a permeate outlet with an inner diameter of 90 mm centered at a position 130 mm from one case end. A thread bundle was inserted. Both ends were bonded with a urethane resin adhesive to seal between the hollow fiber membranes and the gap between the case and the hollow fiber membrane, and then the portion protruding from the case end was cut off to open the hollow fiber membrane. The effective length of the hollow fiber membrane (the length of the portion not buried in the sealing portion) was 890 mm. A stainless steel cap was attached to both ends of the case, and a stainless steel dispersion plate was attached to the permeate outlet to form a membrane module.

(Measurement method of water permeability of membrane module)
A schematic flow diagram of the apparatus used for measuring the water permeability of the membrane module is shown in FIG. The water temperature was adjusted to 25 ± 1 ° C., and the flow rate and pressure were adjusted by adjusting the flow rate adjusting valves 2101, 2102, 2103, and the total amount filtration operation was performed. At that time, the feed water temperature, the permeate flow rate and the operating pressure were measured. As the supply water, water in which tap water was permeated through a reverse osmosis membrane was used. The transmembrane pressure difference P was set to P = (P1 + P2) / 2−P3 with respect to the pressures P1, P2, P3 of the pressure gauges 2201, 2202, 2203.

(Examples 1 and 2 and Comparative Example 1)
Three test modules were manufactured by changing the values of Lf and Lb into a circular shape having a case inner diameter of 300 mm and a hollow fiber membrane bundle having an outer diameter of 280 mm. When the transmembrane pressure difference required to obtain a permeate flow rate of 18 m ³ / hr was measured for each, when Lf / Lb = 1 (Comparative Example 1), the transmembrane pressure difference was 45 kPa. On the other hand, when Lf / Lb = 3, 1.5 (Examples 1 and 2), the transmembrane pressure difference was 32,36 kPa, and the effect of reducing the transmembrane pressure difference was recognized. Together with other examples, the measurement results are summarized in Table 1 and FIG.

(Example 3)
In Comparative Example 1, end bonding was performed in a state where the cross-sectional shape of the hollow fiber membrane bundle was distorted using the dispersion plate from the permeate outlet 110, and the test module was set as Lf = 20 mm, Lb = 10 mm, Lf / Lb = 2. Produced. As in Comparative Example 1, when the transmembrane pressure difference required to obtain a permeate flow rate of 18 m ³ / hr was measured, the transmembrane pressure difference was 33 kPa, and an effect of reducing the transmembrane pressure difference was recognized. Together with other examples and comparative examples, the measurement results are summarized in Table 1 and FIG.

(Examples 4 and 5 and Comparative Example 2)
Three polyethylene nets having a thickness of 2 mm were stacked to form a small bundle water-permeable filler having a width of 280 mm and a length of 1.2 m. Insert one small bundle of water-permeable fillers in the radial direction of the hollow fiber membrane bundle on the left, cover the outer periphery of the bundle with a polyethylene mesh (thickness 2 mm), and form a hollow fiber membrane bundle in a circular shape with an outer diameter of 280 mm. It was. The case inner diameter was set to 300 mm as in Example 1, and three test modules were manufactured by changing the values of Lf and Lb. When the transmembrane pressure difference required to obtain a permeate flow rate of 18 m ³ / hr was measured for each, the transmembrane pressure difference was 35 kPa when Lf / Lb = 1 (Comparative Example 2). On the other hand, when Lf / Lb = 3, 1.5 (Examples 4 and 5), the transmembrane pressure difference was 30, 31 kPa, and an effect of reducing the transmembrane pressure difference was recognized. Together with other examples, the measurement results are summarized in Table 2 and FIG.

(Example 6)
In Comparative Example 2, the width of the water-permeable filler was 275 mm, the outer shape of the hollow fiber membrane bundle was an ellipse having a major axis of 285 mm and a minor axis of 275 mm, the minor axis was directed to 0 °, Lf = 20 mm, Lb = 5 mm, Lf / Lb = 4. As in Comparative Example 2, when the transmembrane pressure difference required to obtain a permeate flow rate of 18 m ³ / hr was measured, the transmembrane pressure difference was 30 kPa, and an effect of reducing the transmembrane pressure difference was recognized. Together with other examples and comparative examples, the measurement results are summarized in Table 2 and FIG.

  According to the fluid separation membrane module of the present invention, the operating pressure can be reduced, and the operating cost can be reduced and the energy efficiency can be improved. In addition, since the cleaning liquid can uniformly clean the entire membrane module during backwashing, there are effects of reducing the frequency of chemical washing and extending the membrane life. These effects are beneficial for users of fluid separation membrane devices.

It is a mimetic diagram of an internal pressure type hollow fiber type water purification membrane module of an example of an embodiment of the present invention. FIG. 1A is a schematic diagram of the entire membrane module, and FIG. 1B is a schematic diagram of the AA cross section of FIG. It is a schematic diagram of an example of the conventional internal pressure type hollow fiber type water purification membrane module. FIG. 2A is a schematic diagram of the entire membrane module, and FIG. 2B is a schematic diagram of the AA cross section of FIG. FIG. 2 is a schematic perspective view of a dispersion plate 600 used in FIG. 1. It is a schematic diagram which shows the flow of the water at the time of filtration of the internal pressure type | formula hollow fiber type water purification membrane module of an example of the embodiment of this invention. FIG. 4A schematically shows a vertical cross section, and FIG. 4B schematically shows a cross section taken along the line AA. It is a schematic diagram which shows the flow of the water at the time of backwashing of the internal pressure type | formula hollow fiber type water purification membrane module of an example of the embodiment of this invention. FIG. 5A schematically shows a vertical cross section, and FIG. 5B schematically shows a cross section taken along the line AA. It is a schematic diagram which shows the flow of the water at the time of filtration of the internal pressure type | formula hollow fiber type water purification membrane module of an example of the other embodiment of this invention. FIG. 6A schematically shows a vertical cross section, and FIG. 6B schematically shows a cross section taken along the line AA. It is a schematic diagram which shows the flow of the water at the time of backwashing of the internal pressure type | formula hollow fiber type water purification membrane module of an example of the other embodiment of this invention. FIG. 7A schematically shows a longitudinal section, and FIG. 7B schematically shows a transverse section taken along the line AA. It is a schematic diagram which shows the example of the other embodiment of the cross section equivalent to the AA cross section in Fig.1 (a) of this invention. It is a schematic diagram of the internal pressure type | formula hollow fiber type water purification membrane module of an example of the other embodiment of this invention. FIG. 9A is a schematic diagram of the entire membrane module, and FIG. 9B is a schematic diagram of the AA cross section of FIG. 9A. It is a schematic flowchart of the apparatus which performed the water-permeable performance measurement of the membrane module in the Example and comparative example of this invention. FIG. 5 is a graph showing the relationship between Lf / Lb and transmembrane pressure difference required to obtain a permeate flow rate of 18 m ³ / hr in Examples 1 to 3 and Comparative Example 1 of the present invention. FIG. 4 is a graph showing the relationship between Lf / Lb and transmembrane pressure difference required to obtain a permeated water flow rate of 18 m ³ / hr in Examples 4 to 6 and Comparative Example 2 of the present invention.

Explanation of symbols

100: Case 110: Permeated water outlet 120: Air vent 130: Drain port 200: Lower cap 210: Lower cap body 220: Lower cap opening 300: Upper cap 310: Upper cap body 320: Upper cap opening 400: Hollow fiber membrane bundle 410: hollow fiber membrane 420: hollow fiber membrane protective cylinder 500: sealing resin 600: dispersion plate
610: Dispersion plate shielding portion 620: Dispersion plate fixing portion 630: Dispersion plate support portion 700: Fastening means 800: Permeate chamber 900: Small bundle water permeable filler 1001: Auxiliary line 2001: Supply water tank 2002: Temperature control device 2003: Stirrer 2004: Supply pump 2005: Membrane modules 2101, 1022, 2103: Flow rate adjusting valves 2201, 2202, 2203: Pressure gauge 2301: Flow meter

Claims (4)

A cylindrical case having one or more permeate outlets on the outer peripheral surface,
A hollow fiber membrane bundle is provided in the cylindrical case,
The hollow fiber membrane bundle is sealed between the hollow fiber type separation membranes and between the hollow fiber type separation membranes and the case at both ends, and the hollow fiber type separation membrane lumens at both ends of the cylindrical case. Is open,
It comprises a substantially annular space in cross section that is a gap between the hollow fiber membrane bundle and the substantially cylindrical case, and comprises a permeate chamber that communicates with the permeate outlet,
With respect to the permeate chamber in a cross section that includes the center of the permeate outlet and is orthogonal to the long axis of the case, Lf is the width on the permeate outlet side and Lb is the width on the opposite side of the permeate outlet. / Lb> 1 is an internal pressure hollow fiber type liquid separation membrane module.   The hollow fiber membrane bundle includes a small-bundle permeation filler that has a maximum length in the case axial direction of 60% or more of the effective length of the hollow fiber membrane and less than the case length and communicates with the permeate chamber. The internal pressure type hollow fiber type liquid separation membrane module according to claim 1.   The internal pressure type hollow fiber type liquid separation membrane module according to claim 1 or 2, wherein a width of the permeate chamber is Lf / Lb≥1.5. The internal pressure type hollow fiber type liquid separation membrane module according to any one of claims 1 to 3, wherein a width Lf of a permeate outlet of the permeate chamber is 20% or less of an inner diameter of the case.

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